Bernstein was born in Lawrence, Massachusetts. He was highly regarded as a director, composer, pianist, and educator. He is probably best known to the public as long time music director of the New York Philharmonic Orchestra; for conducting concerts by many of the world's leading orchestras; and for writing the music for the musical West Side Story. All told, he wrote three symphonies, two operas, five musicals, and numerous other pieces. Bernstein's politics were decidedly left wing, but unlike some of his contemporaries, he was not blacklisted in the 1950s.

During the 1960s, he became a well-known figure in the US through his series of "Young People's Concerts" for US public television.

On Christmas Day, December 25, 1989 Bernstein conducted Beethoven's Symphony No. 9 as part of a celebration of the fall of the Berlin Wall. The concert was broadcast live in more than twenty countries to an estimated audience of 100 million people. For the occasion, Bernstein reworded Friedrich Schiller's text of “Ode to Joy”, substituting the word "freedom" (Freiheit) for "joy" (Freude). "I'm sure that Beethoven would have given us his blessing", said Bernstein.

Bernstein was a highly-regarded conductor among many musicians, in particular the members of the Vienna Philharmonic Orchestra, of which he was a regular guest conductor. However, some people found his histrionic conducting style irritating and distracting; he danced and went into fits of exultation as he conducted.